Hello everyone,
Now that I have the AG Optical FA12 (12.5", f/5, fl 1570mm), with a stated corrected field of 50mm, I am trying to make sure I am utilizing as much of that cone of light as possible. My imaging train currently is a little bit weird and not typical, simply because it is what I had right now to get it to image at all. Before I go on buying spree of a bunch of expensive adapters and focusers, I want to make sure they will materially improve the image, and that they are necessary.
Here is my imaging train:
Back of the OTA baffle is an Optec 3600 male dovetail on a tip/tilt plate > Optec Leo focuser (31mm thickness >Optec 3000 to 3.29" SCT threads adapter> Baader Diamond Steeltrack SCT focuser> M68 30mm extension> M68 ZWO tilt plate > OAG-L> ZWO 2" 7 position EFW>6200mm pro (The OAG/EFW/Camera are bolted together in one unit).
You might ask why I have two focusers. It is because the Optec Leo came with the OTA, and I don't have any Optec 3600 > 3.29" adapters yet, or any SCT>M68mm adapters yet. I curretly use the ZWO EAF to focuse. The Optec Leo focuser is just being used as an adapter here.
So after this introduction to the imaging train, here is my question:
I do notice a steep drop off in the light in the corners of my full frame 6200mm pro with the 50mm round filters. That drop off does calibrate out with flat frames however to produce an acceptable result.
The question is, is this what everyone sees when using an f/5 scope on the 6200mm or other full frame sensors and a 50mm round filter? Or am I being constrained by my 2" Baader Steeltrack focuser?
Here is an example of what my flat frame looks like with an autostretch. With my light frames I do see stars all the way to the corner so it is not zero illumination, just a significant drop off that calibrates well with flat frames.
Flat frame example with autostretch:
These are the only two examples of the two targets that I managed to image so far since I got this OTA last week (just about 4 hours for each target, so not much time) after full calibration and post processing. Note that I only cropped a minor amount for stacking artifacts (about 50-100 pixels in each axis). So this is pretty much near the full frame sensor size:
These are narrowband images. I did not test it with a broadband target just yet to see if the flat frames work well for those filters. I suspect it will be harder.
Do you think using a 3" focuser for the entire imaging train would improve the vignetting? Or what I am seeing is normal and expected with an f/5 system and this is the limit of a 50mm round filter on a full frame sensor?
Thanks.
Now that I have the AG Optical FA12 (12.5", f/5, fl 1570mm), with a stated corrected field of 50mm, I am trying to make sure I am utilizing as much of that cone of light as possible. My imaging train currently is a little bit weird and not typical, simply because it is what I had right now to get it to image at all. Before I go on buying spree of a bunch of expensive adapters and focusers, I want to make sure they will materially improve the image, and that they are necessary.
Here is my imaging train:
Back of the OTA baffle is an Optec 3600 male dovetail on a tip/tilt plate > Optec Leo focuser (31mm thickness >Optec 3000 to 3.29" SCT threads adapter> Baader Diamond Steeltrack SCT focuser> M68 30mm extension> M68 ZWO tilt plate > OAG-L> ZWO 2" 7 position EFW>6200mm pro (The OAG/EFW/Camera are bolted together in one unit).
You might ask why I have two focusers. It is because the Optec Leo came with the OTA, and I don't have any Optec 3600 > 3.29" adapters yet, or any SCT>M68mm adapters yet. I curretly use the ZWO EAF to focuse. The Optec Leo focuser is just being used as an adapter here.
So after this introduction to the imaging train, here is my question:
I do notice a steep drop off in the light in the corners of my full frame 6200mm pro with the 50mm round filters. That drop off does calibrate out with flat frames however to produce an acceptable result.
The question is, is this what everyone sees when using an f/5 scope on the 6200mm or other full frame sensors and a 50mm round filter? Or am I being constrained by my 2" Baader Steeltrack focuser?
Here is an example of what my flat frame looks like with an autostretch. With my light frames I do see stars all the way to the corner so it is not zero illumination, just a significant drop off that calibrates well with flat frames.
Flat frame example with autostretch:
These are the only two examples of the two targets that I managed to image so far since I got this OTA last week (just about 4 hours for each target, so not much time) after full calibration and post processing. Note that I only cropped a minor amount for stacking artifacts (about 50-100 pixels in each axis). So this is pretty much near the full frame sensor size:
These are narrowband images. I did not test it with a broadband target just yet to see if the flat frames work well for those filters. I suspect it will be harder.
Do you think using a 3" focuser for the entire imaging train would improve the vignetting? Or what I am seeing is normal and expected with an f/5 system and this is the limit of a 50mm round filter on a full frame sensor?
Thanks.
